1. Field of Invention
The present invention relates to a method and an apparatus for reducing electric power consumption. More particularly, the present invention relates to a method and an apparatus for controlling the performance of a performance controllable circuit according to load states, thus controlling the peripheral apparatuses of the circuit, so as to provide different performances on various demands and achieve an optimal power-saving effect without affecting the normal operation of the system.
2. Description of Related Art
Recently, along with the progress in electronic science & technology, a variety of electronic products has entered our work and life. Especially, the emergence of computer has a great impact on us. At present, the types of a common personal computer (PC) include a desktop computer and a portable computer, wherein the type of the portable computer further includes notebook PCs, pocket PCs, tablet PCs and so on.
In a computer system, the CPU consumes most power for the power consumption of the whole system. The power consumption of the CPU is increased with the raising of the operating frequency and the core voltage. For portable electronic devices operated by cell, such as mobile phones, pocket PCs (personal digital assistants), digital cameras and notebook PCs, an important topic is to reduce the power requirement of the CPU.
A conventional notebook PC is provided with a software system designed for manually adjusting the CPU performance. The software system provides various performance settings for the CPU. When a user wants a high performance, the software can be manually adjusted, such that the software can control the CPU to operate at a relatively high frequency for providing a relatively high performance.
However, as for manual adjustment, when the notebook PC is idle, if the user forgets to turn down the operating frequency of the CPU via the software system, the heat-sink fan keeps on rotating at a high speed, thus causing noises and reduction of the duration of the cell. In another aspect, when the user is executing an arduous program, if the user forgets to raise the operating frequency of the CPU via the software system, the notebook PC may not operate smoothly, thus affecting the normal operation of the operating system of the notebook PC.